Rotation for rock drills



, INVENTOR 1 a /es Hi5 ATTOR I Y L. c. BAYLES ROTATION FOR ROCK DRILLS Filed Feb. 18, 1924 Patented Apr. 28, 1925.

UNITED STATES LEWIS C. BAYLES, OF EASTON, PENNSYLVANIA,

COMPANY, OF JERSEY CITY, NEVI ASSIGNOR TO INGERSOLL-RAND JERSEY, A CORPORATION OF NEW JERSEY.

ROTATION FOR ROCK DRILLS.

Application filed February 18, 1924.

To aZZ whom it may concern:

Be it known that I, Lnwis C. BAYLES, a citizen of the United States, and a resident of llaston, county of Northampton, and

State of Pennsylvania, have invented a certain Rotation for Rock Drills, of which the following is a specification, accompanied by drawings.

This invention relates to rock drills and more particularly to mechanism for rotating the drill steels.

In certain types of rock drills,the rotation of the drill steel is effected by making the piston rotate the chuck in which the drill steel shank is inserted. The piston is itself provided with a rifle nut within which a rifle bar is inserted so that as the piston reciprocates, the rifling causes a rotation thereof in one direction either on the forward or back stroke, depending upon the design of the drill. The rifle bar is held stationary on one stroke and rotated on the other; for instance, if steel rotation is desired on the forward stroke of the piston,

the rifle bar is held stationary on that stroke, while on the back stroke of the piston the rifle bar is free to rotate and the piston does not turn. In this manner the drill steel is rotated in only one direction which condition produces the most satisfactory results in drilling. While the rifle bar is free to rotate on one stroke, on the other it is held against rotation by a suitable ratchet mechanism cooperating with portions at the back of the drill cylinder. One type of ratchet mechanism employed consists of a head on the rifle bar carrying spring pressed pawls which cooperate with a stationary ratchetring at the back head. The pawls are normally pressed outwardly to engage the ratchet ring by means of plungers pressed against the under face of the pawls. On account of the springs under the plungers it is somewhat diflicult to assemble the pawls in the rifle bar head and to keep them in proper position while inserting the rifle bar in the ratchet ring.

It is accordingly an object of this invention to arrange the pawl plungers and pawls in such a manner that the former normally holds the latter in place in the rifle bar head and permits the removal of the pawls without difliculty when desired.

()ther objects of the invention will become apparent hereinafter.

. head with the drill steel inserted in a chuck for maintaining Serial No. GSZAYO.

The drawing illustrates one embodiment which the invention may assume in practice.

Figure 1 is a longitudinal sectional view of a portion of a rock drill showing the'rifle bar, ratchet mechanism and the associated parts.

Figure 2 is a top view of the rifle bar pawls and pawl plungers in position, parts being broken away to show the internal arrangement of the pawl plungers and pawls, a part of the ratchet ring being shown also, and

Figure 3 isa perspective view of one of the pawls removed from the rifle bar head.

In Figure 1 there is shown the cylinder A of a rock drill provided with a front washer B which seals and closes the forward end, and a rotation washer C closing the rearward end. A piston D of any suitable description is adapted to reciprocate in the cylinder A under the influence of compressed air or other motive fluid admitted to the rearward and forward ends of the cylinder through suitable ports (not shown) and educted through suitable exhaust ports E. The piston D is provided with a nose F which projects through the cylinder front washer B and which strikes the rear end of not shown). As is common in drills of this character, the nose F of the piston is fluted at its end to cooperate with suitable parts it in fixed rotation relation with the chuck holding the drill steel. Rotation of the chuck is accomplished by rotating the piston D and to this end there is provided a rifle bar G extending through the rotation washer C and cooperating with a rifled or piston nut H secured in any suitable manner as by a screw thread in the head of the piston D. The rear end of the rifle bar G is in the form of a disc J and is known as the rifle bar head. The rifle bar head has a rear bearing K in the back head 0 of the drill. The forward thrust of the rifle bar is taken by the rotation washer C.

Ordinarily it is desired to rotate the steel (and consequently the piston. D) in only one direction. Rotation may take place 011 either the forward stroke of the piston D or on the back stroke, depending upon the character of the drill and the drilling conditions to which it is subject. The rifle bar G is held against rotation in one direction so that as the piston D moves forwardly or IOU llU

rearwardly as the case maybe, the flutes on the rifle bar cooperating with the rifle nut l-l cause the piston to turn slightly. On the other stroke of the piston D, the rifle bar is tree to rotate in the opposite direction but the piston does not rotate because of the greater mass of the piston, chuck and steel.

In order to prevent the rifle bar G trom rotating in one direction, there is provided a ratchet ring P inserted between the back head O and the cylinder A and rotation washer C and held stationary thereby. Suitable pawls Q are mounted in the edge ot the rifle bar head d to cooperate with the teeth on the inside of the ratchet ring. The ratio ol. the nmnber ot teeth on the ratchet ring P to the number of pawls (Q. is a traction, for example, it there are tour pawls Q, the number 0t teeth on the ratchet ring P may be 37, so that at any moment only one ot the pawls Q: is in engagement with the teeth of the ratchet ring. T he reason tor arranging the pawls and teeth in this manner, is so that there will be the least back lash in the ratcl'iet mechanism, upon the reversal of the direction of motion of the piston D.

One of the pawls Q is shown in perspective in Figure 3. Each pawl has a cylindrical bearing end which tits accurately in a similarl formed aperture S in the rifle bar head. Integral with the bearing end B there is a flattened square ended tongue T which extends outwardly beyond the edge ot the rifle bar head to engage the teeth of the ratchet ring P. The pawls are pressed into engagement with the teeth of the ratchet ring P by means of cylindrical plungers U which it slidably in the cylindrical holes V bored substantially perpendicular to the in nor face of the tongue T in its normal position. Suitable coil springs VJ press the plunger-s U against the tongue T of the pawls. The holes X extend trom the partof the holes V into the adjacent apertures b so that should a plunger U stick down in one ot the holes V a suitable instrument may be inserted through the hole X to push it out.

When the rotation of the rifle bar head is rapid the motion of the pawls Q is such as to cause a considerable motion in the plungers U and the force directed by the pawls against the plungers is sutiicient to produce great strain on the spring VJ. For this reason the plungers are arranged to press against the tongues T near the bearing R as possible. This produces relatively little motion in the plungcrs U so that the momentum thereof is insutlicient to crush the spring beneath.

lVhen the rifle bar is removed from the drill, the tendency of the pawls is to slide from their mounting on the rifle bar head because the tension of the springs \V is relieved when the tongues 'l are in their ontermost position. It therefore becomes a matter of great convenience to lock the pawls in their bearings against accidental removal. To this end there is provided a means which automatically locks the pawl against removal except for certain positions of the pawl. Preferably this means includes the plungers U and parts of the pawls themselves.

Referring to Figure 3 the cylindrical bearing end R- of the pawl is notched at Y to permit the plunger U to bear on the tongue T and cooperate with the sides of the notches Y to keep the pawl from moving laterally. The outer head of the plunger U is rounded slightly so that when the tongue T' is pressed down flat against the face of the rifle bar head, the plunger extends far enough intoits cylindrical hole V to clear the edges of the notch Y. This is shown most clearly in Fig. 2, the pawl at the left being shown pressed down, pushing the plunger U back so as to disengage the notch Y. When in this position, the pawl may easily be removed by sliding it sidewise in the aperture S. However when the pawl is not depressed, as for instance, the uppermost pawl in Fig. 2, it is locked against removal by the plunger engaging in the notch Y.

I claim:

1. In a rock drill, automatic rotation mechanism comprising a rifle bar haring a head, a ratchet ring encircling said. head, pawls mounted in said head and cooper-ah ing with said ratchet ring to prevent rotation of said rifle bar in one direction, spring pressed plungers for said pawls, said pan being notched to admit said plnngcrs whereby said pawls are locked against removal trom said head.

2. In a rock drill, automatic rotation mechanism comprising a rifle bar having a head, a. ratchet ring encircling said head. pawls in said head cooperative with said ratchet ring to prevent rotation of said rifle bar in one direction, spring pressed plunger-s for said pawls, said pawls being notched to admit plungers, whereby said pawls are locked against removal from said head, said plunger-s having a head to contact with said pawl and arranged to unlock said pawl when said pawls are depressed.

In testimony whereof I have signed this specification.

LElVIS C. BAYLES. 

